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  1. duke37

    Can't figure out capacitor value

    I would guess that the .022J capacitor is 0.022microF i.e. 22nF. (A preferred value) The J is probably the dielectric. The 331 is the value in pF as marked on resistors (3 3 and one 0) so 330pF. Somewhat confusing!
  2. duke37

    Wireless Distance Proportional Signal Circuit Help

    Maplin have an ultrsonic sonar ranging IC - N17KK.
  3. duke37

    Need help with pendulum clock

    I Googled free pendulum clock and got an article by Ron Elliot which has a couple of diagrams. sound.westhost.com/clocks/free-pendulum.html His clock failed because of corrosion of the very fine coil wire. Have you tested the coil for continuity? Duke
  4. duke37

    DC/DC Power Supply Help

    Dropping 24V to 12V using a resistive circuit will give an efficiency of 50%. To get a higher efficiency, you will need to store the energy in an inductor and send it to the output. Pulse width modulation will be needed to do this and will enable a constant output voltage with varying load and...
  5. duke37

    Wireless Distance Proportional Signal Circuit Help

    I suggest using an ultrasonic transducer to generate a pulse and a similar transducer to receive the pulse. It may be possible to use a reflector at point B rather than an active device. You will need to research how the transducer is driven and make a simple circuit to drive it. If you wish...
  6. duke37

    powering a micro controller from mains ac

    Could you use two zener diodes, back to back, instead of a resistor?
  7. duke37

    Need help with pendulum clock

    Wecome Redeye, I feel like that this morning The most likely fault with the clock is bad battery connections - measure the voltage on the printed circuit board. The coil may have corroded and be open circuit, check with a meter. The capacitor may be faulty - easier to check by subsitution...
  8. duke37

    Electrolytic Capacitors

    Since the capacitor is near the flyback transformer, perhaps it has to deal with high current pulses. Try to get the specification of the old capacitor and then find a better one if possible. Voltage Capacity Temperature Ripple current ESR
  9. duke37

    Electrolytic Capacitors

    Perhaps there is a high ripple current at this point and you need a capacitor with a low series resistance.
  10. duke37

    Electronic ORGAN repair question

    It depends on whether the organ is transistorised or valved. A 100k resistor in series with a 100nF capacitor should protect the radio in most cases and pass sufficient signal.
  11. duke37

    Electronic ORGAN repair question

    Do you have an audio system with provision for external input? Failing this, use a portable radio with the input across the volume control.
  12. duke37

    Bulb Protection

    You are still confused between current and voltage. A led outputs an amount of light roughly proportional to the CURRENT, the voltage changes little, it is not similar to a bulb. A bulb works by heating a wire and on low voltage, the wire is not hot and gives out no light. Efficiency rises as...
  13. duke37

    Bulb Protection

    A device can be designed to supply a certain current, if you take more current than it is intended for, then it may fail due to overheating. A sling used with a crane is rated at a certain maximum tension. If this is exeeded the sling may break. Your regulator can happily supply 3A but may...
  14. duke37

    Run an mp3 player on a car battery?

    I do not know too much about batteries but starter batteries are intended to provide a large starting current and then be recharged immediately. Deep cycle batteries are not intended to provide high currents so may be better in this application.
  15. duke37

    Bulb Protection

    Do not get mixed up between voltage and current. A 12V 35W bulb will take about 3A., if you do not have the ability to supply 3A then the voltage will be lower than you think. With your 100mA supply, the voltage would be very low. With your 5V supply the voltage is low and the bulb MAY be...
  16. duke37

    Bulb Protection

    I have done a Google and see that the Pulsar has had electrical problems. There is a circuit diagran on the web and it shows a B/Y (black/yellow?) wire from the regulator to frame. This is the one I would look at first. Best of luck.
  17. duke37

    Bulb Protection

    I am not familiar with motor cycle electrics but assume they are similar to car electrics. The alternator will produce a voltage proportional to its rotational speed and will need some form of control to keep it within bounds. There will be two output connections, one will go to the switches and...
  18. duke37

    frequency question

    It is not so much the frequency as the bandwidth. A TV channel needs a bandwidth of 4 or 5MHz so if you used a low frequency, this would take the whole of long wave, medium wave and a considerable amount of short wave. At the very high frequencies there is more room and it is easier to make...
  19. duke37

    Run an mp3 player on a car battery?

    Car batteries will sulphate if left discharged. I suggest scaling for one month and re-charging each week. It should be simple to turn off the device when it is dark, so saving power.
  20. duke37

    Bulb Protection

    If the bulbs are blowing, you are peddling your bike too fast! The rectifier may not be just a rectifier but also a voltage regulator. Get a circuit diagram to check. If it is a regulator, it will need an earth reference, check for bad connections to the frame.
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